Rich countries - including New Zealand - have reduced the amount of damaging cholesterol in their citizens' diets over the past 40 years, a global study has found, despite the popularity of high-fat, low-carb diets.
But rates of both high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol have increased in poorer nations, especially in the Pacific and China.
Non-HDL cholesterol is the bad type, and responsible for nearly 4 million deaths annually, the researchers said.
"The decrease in non-HDL cholesterol in Western countries started in the 1980s, before statins were widely used," the researchers said.
"This indicates that changes in diet, especially the replacement of saturated with unsaturated fats and reduction in trans fats are major contributors to this decline... In contrast to high-income Western countries, the consumption of animal-source foods, refined carbohydrates and palm oil has increased substantially in east and southeast Asia where statin use remains low."
Countries with particularly high rates of cholesterol in 1980 such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta have been overtaken by the likes of Tokelau, Malaysia, the Philippines and Thailand.
University of Auckland cardiovascular disease epidemiologist Prof Rod Jackson told Newshub staying away from high-fat, low-carb diets - such as Atkins - is a good idea if we don't want the trend to reverse.
"Those diets tend to have a short-term effect on weight, but in the long-term there's increasing evidence that they do far more harm than good... it is possible that these really good changes may actually go in the other direction if we're not careful."
Prof Jackson says heart disease, brought on by high levels of non-HDL cholesterol, can sneak up on people if they don't eat well.
"The first symptom is death - that's the most devastating thing about heart disease... it can be a very silent disease."
The study, which looked at more than 1100 studies covering 102 million people across the globe, was run by the British Heart Foundation and published in journal Nature.
Overall it found the gains made in wealthy nations were offset by the losses in poorer countries, so overall there was "little change in total or non-HDL cholesterol from 1980 to 2018".
The scientists said that the study's findings "should motivate the use of policies that help replace saturated fats with unsaturated fats and to enhance treatment throughout the world".
